Rucksack



FIG. 1 is a front perspective view of a rucksack showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a rear plan view thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a side elevation view thereof; the opposite side elevation view being a mirror image of the view shown in FIG. 6. 

The ornamental design for a rucksack, as shown and described. 